The government of Prime Minister Silvio Berlusconi had taken a hard-line approach to immigration, cracking down on those in Italy illegally. And now the Italians have begun to see the results and are pleading for the government to exempt foreign cleaners and nannies from the crackdown.

In the United States, there is no nanny shortage now —and. of course, not all nannies are immigrants — but a major change in immigration laws, or an increased crackdown on those in this country illegally, could severely limit the pool of available nannies.

"I think that the evidence here is clear … if you take child care away, we'd have many fewer women in the work force," said Jonathan Gruber, an economics professor at MIT who studied child care issues in Canada. "Child care availability is the key determinant of female labor force participation."

As more women entered the working world in the past few decades, Gruber said, "It's not like the dads are filling in. It's just increasingly that children are being cared for in child care settings."

Let's say -- hypothetically -- that 10 percent of the 65.7 million women in the work force today decided to stay home. That would mean a sudden shortage of about 6.6 million workers. Productivity would plummet and millions of dollars would stop flowing through the economy.

The average American makes $31,333 a year. That means that if just 10 percent of the women working in the United States today decided to stay home, about $206 billion in wages would be lost. There would also be a dramatic impact on federal and state income taxes if such a mass of women fled the work force.

Liz Ryan, a workplace expect and author, said such a nanny shortage such as the one feared in Italy would be "catastrophic" here.

"Many of these women, if they had to pay a legal nanny, they couldn't work," Ryan said.

Many women have become disenchanted with corporate America and are starting their own businesses, said Ryan.

"We already have a big problem with women bolting the workplace," Ryan said. "To add on top of that a child care crisis would set women back professionally 20 years, at least."

There are 23 million children under the age of 6 — the typical age when kids enter school — living in the United States, according to the U.S. Census Bureau. Of those, 14.3 million, or about 62 percent, live in households where all the adults work, either a two-parent house with two working parents or a single parent who works.

Women make up 46.3 percent of the labor force but hold 50.6 percent of the positions in management and professional occupations, according to Catalyst, an organization that promotes women in the workplace.